/**
  External libraries used by altPreso.
**/

/**
  A subset of Prototype JavaScript framework version 1.3.1
  (c) 2005 Sam Stephenson <sam@conio.net> <http://prototype.conio.net/>
**/
function $() {
  var elements = new Array();

  for (var i = 0; i < arguments.length; i++) {
    var element = arguments[i];
    if (typeof element == 'string')
      element = document.getElementById(element);

    if (arguments.length == 1) 
      return element;

    elements.push(element);
  }
	
  return elements;
}

document.getElementsByClassName = function(className) {
  var children = document.getElementsByTagName('*') || document.all;
  var elements = new Array();
  
  for (var i = 0; i < children.length; i++) {
    var child = children[i];
    var classNames = child.className.split(' ');
    for (var j = 0; j < classNames.length; j++) {
      if (classNames[j] == className) {
        elements.push(child);
        break;
      }
    }
  }
	
  return elements;
}

var Element = {
  addClassName: function(element, className) {
    element = $(element);
    Element.removeClassName(element, className);
    element.className += ' ' + className;
  },

  hasClassName: function(element, className) {
    element = $(element);
    if (!element)
      return;
    var a = element.className.split(' ');
    for (var i = 0; i < a.length; i++) {
      if (a[i] == className)
        return true;
    }
    return false;
  },
	
  removeClassName: function(element, className) {
    element = $(element);
    if (!element)
      return;
    var newClassName = '';
    var a = element.className.split(' ');
    for (var i = 0; i < a.length; i++) {
      if (a[i] != className) {
        if (i > 0)
          newClassName += ' ';
        newClassName += a[i];
      }
    }
    element.className = newClassName;
  }
};

/**
  Workaround for Gecko's DOM Phantom Whitespace Issue.
  Adopted the solution by L. David Baron at
  <http://developer.mozilla.org/en/docs/Whitespace_in_the_DOM>
**/

/**
 * Throughout, whitespace is defined as one of the characters
 *  "\t" TAB \u0009
 *  "\n" LF  \u000A
 *  "\r" CR  \u000D
 *  " "  SPC \u0020
 *
 * This does not use Javascript's "\s" because that includes non-breaking
 * spaces (and also some other characters).
 */

/**
 * Determine whether a node's text content is entirely whitespace.
 *
 * @param nod  A node implementing the |CharacterData| interface (i.e.,
 *             a |Text|, |Comment|, or |CDATASection| node
 * @return     True if all of the text content of |nod| is whitespace,
 *             otherwise false.
 */
function is_all_ws( nod )
{
  // Use ECMA-262 Edition 3 String and RegExp features
  return !(/[^\t\n\r ]/.test(nod.data));
}

/**
 * Determine if a node should be ignored by the iterator functions.
 *
 * @param nod  An object implementing the DOM1 |Node| interface.
 * @return     true if the node is:
 *                1) A |Text| node that is all whitespace
 *                2) A |Comment| node
 *             and otherwise false.
 */
function is_ignorable( nod )
{
  return ( nod.nodeType == 8) || // A comment node
         ( (nod.nodeType == 3) && is_all_ws(nod) ); // a text node, all ws
}

/**
 * Version of |firstChild| that skips nodes that are entirely
 * whitespace and comments.
 *
 * @param sib  The reference node.
 * @return     Either:
 *               1) The first child of |sib| that is not
 *                  ignorable according to |is_ignorable|, or
 *               2) null if no such node exists.
 */
function first_child( par )
{
  var res=par.firstChild;
  while (res) {
    if (!is_ignorable(res)) return res;
    res = res.nextSibling;
  }
  return null;
}